Field of the Invention
The present invention generally relates to marine trimming systems and, more particularly, to a rudder configured for steering and trimming a marine vessel.
Discussion of the Related Art
Flaps and trim tabs are known for influencing primarily roll and pitch movements of marine vessels to control listing and assist planing of the vessels so that the vessels can be stabilized at a desired attitude. This is typically accomplished by one or more flaps or trim tabs coupled, attached, or otherwise carried by a larger component or structure of the vessel, such as on a lower portion of a transom wall of the vessel. As is generally understood, adjustments are typically carried out by adjusting an angle of the flaps or trim tabs relative to the larger component or structure.
Flaps and trim tabs of the kind generally known in the art have a single degree of freedom of movement with respect to the component to which they are mounted. Each of the flaps and trim tabs pivots about a single pivot axis that is typically arranged generally horizontally so that up and down pivoting of the flap or trim tab provides a pitch-type rotation that defines the single degree of freedom of movement. Pivoting a flap or trim tab down presents a relatively large surface area to the water and increases hydrodynamic appendage drag. This provides negative lift by way of reactionary forces to the hydrodynamic appendage drag that roll and/or pitch the vessel to oppose a non-desired oppositely directed roll and/or pitch that is being corrected to reduce listing or assist planing of the vessel.